Spreadsheet applications for computers, such as IBM's Lotus 123® and Microsoft® Excel, have become very popular analysis and communication tools. Spreadsheets are typically used to perform numerical analyses and ‘what if’ analyses, to simulate complex systems, and to communicate ideas. Many users are familiar with the spreadsheet metaphor. With little or no training, users can create complex, interrelated calculations and data transformations in spreadsheet applications.
The rapid growth and adoption of the Internet has spawned an explosion in web-based distribution of application functionality and server-based applications. Many such distributed and server-based applications have underlying logic that comprises complex calculations and data transformations. Development of such functionality in software language source code can be effort intensive, tedious, and error-prone. Furthermore, creating such functionality requires highly skilled software developers.
Being able to embed the calculations and data transformations of a spreadsheet directly into stand-alone applications, distributed applications, and server-based applications can be very powerful. Some spreadsheet applications have application programming interfaces (APIs) that allow them to provide calculation and data transformation as a service to other applications. But distributing and using spreadsheets in this way requires that users have the same or a compatible spreadsheet application as the one in which the spreadsheet was created.
Using spreadsheet applications as calculation engines in server-based applications also has limitations. Background art spreadsheet applications are meant for single users and cannot scale to support high-volume server-side processing. Also, the User Interface and display features of spreadsheet applications carry significant overhead.
There are background art spreadsheet components available that can read and write spreadsheet data created by popular spreadsheet applications and perform calculations at runtime. These components do facilitate the integration of spreadsheet functionality into other distributed applications or server-based applications. But these components operate internally in the same way spreadsheet applications do: they interpret Cell formulas at runtime. Runtime interpretation of Cell formulas is generally considered to be a desirable feature because it allows Cell formulas to be changed at runtime. But in many application scenarios, calculations and data transformations need to remain unchanged at runtime. So when a spreadsheet component is used as a calculation engine in such an application, then the runtime Cell formula interpretation feature adds memory and processing overhead without adding any value. Background art spreadsheet components are typically larger than 1 Megabyte in size.
When using background art spreadsheet components in server-based applications, the overhead associated with the User Interface and runtime cell formula interpretation features can negatively impact server performance, both from processing speed and memory usage standpoints. When using background art spreadsheet components in distributed applications, the overhead can also significantly degrade download performance.
Some spreadsheet applications and spreadsheet components use mechanisms to represent simple cell formulas as machine code during idle time processing. While this can reduce the negative performance impact related to run-time cell formula interpretation, it maintains the memory overhead and it can limit the spreadsheet application or spreadsheet component to running on only a single platform.
It would be desirable to provide a facility for automatically generating source code from spreadsheet data such that the generated source code embodies the calculations and data transformations embodied in the spreadsheet data. The generated source code may then be integrated into a wide variety of different types of applications or other utilization mechanisms. The calculations and data transformation may allow features to be accessed by users who do not have a spreadsheet application or spreadsheet component, or who have a spreadsheet application or spreadsheet component that is incompatible with the original spreadsheet application. The calculations and data transformation may protect features from being modified accidentally or deliberately. Thus, spreadsheet applications may be used as design tools for creating and testing complex, interrelated calculation functionality for use in a wide variety of applications. The calculations and data transformation allows features to be embedded into high-volume server architectures, such as mainframe computers or super computers, that are not fully supported by background art spreadsheet applications or components. Moreover, the calculations and data transformation may allow features to be embedded into disparate or distributed computing environments, such as web-browsers, embedded systems, gaming consoles, cell phones, and personal digital assistants (PDAs), that are not fully supported by background art spreadsheet applications or components.
One of the most labor-intensive aspects of software development is testing to verify that the software meets specifications. In many software development efforts, major parts of the system must be built before any of the parts can be tested. This makes it difficult to localize the origin of errors. But when using a spreadsheet to develop the core logic of a system it is easy to create multiple sets of test data and switch between the sets to test the spreadsheet. Therefore, it would be desirable to provide a core functionality that can be verified locally, before deployment and without writing any code.